The use of refrigerants to keep items cool is widespread, both for transportation of heat sensitive or heat damageable products and for long term storage of the products. Refrigerators and refrigerated transport systems can be used for storage and transportation of large scale products, but may not be available for small scale products such as short haul delivery systems, airline transportation, and home and recreational cooling of foods, beverages and the like.
The use of ice, dry ice, or blue ice to keep products at a cool temperature has been used extensively for many years. For example, the general public widely uses insulated containers packed with ice to maintain foodstuffs and beverages cool when camping, travelling or on picnics and the like. Ice is also used commercially to pack foodstuffs, flowers, plants and the like for transportation and storage until sold or until placed in a refrigerator. Ice is also used in the medical field to reduce trauma, swelling and pain from injuries of all kinds, and to transport and store blood, tissue, organs, pharmaceuticals and the like. The use of ice, dry ice, or blue ice as a coolant material serves as a preservative and inhibits the growth of harmful microorganisms.
The major drawback to the use of ice as a coolant material is that it melts and is no longer an effective packaging material. The melted ice is easily contaminated by microorganisms which, since it will be in intimate contact with the products it is protecting, is also liable to contaminate the products. The items may also be damaged by getting wet. The melted ice may also allow the products to move or slosh around in the container, risking damage by impact with the walls of the container. Moreover, the container itself must also be waterproof or the water and the products will break out of the container.
Dry ice also has some disadvantages. It is converted into CO2 with time and thus the gas must be dissipated and the product will not be packed against movement in its container or be kept cool. Both water and dry ice can be used only once, adding to the expense of thermal storage.
Blue ice may be used repeatedly by refreezing the contents of the bag or block. However, blue ice is brick hard when frozen into a solid block and becomes soft and pliable as the material melts within the bag.
Ice, dry ice, and blue ice may be used to keep items or products cool, however, a user has no control over the temperature of the container or the products. Currently, there is no way to maintain the temperature of products unless a refrigerator or refrigerated transport system is used. Moreover, when used, the ice, dry ice, and blue ice move around within the package that may create temperature variances within the packaging. Thus, some parts of the products may be cool while other parts are warm.
Thus, there is a need for an apparatus and method that allows a user to maintain a constant known temperature over an extended period of time in a container without the use of refrigerators or refrigerated transport systems at an economical cost. Moreover, there is a need for a reusable apparatus that allows a user to maintain a constant known temperature in a container with little to no temperature variances within the packaging.